Casting from QByteArray to const BYTE* in a function call

Hi,
This is my first post and I haven't seen if this was discussed previously. Apologies if it has and was answered.

Using a library that I link into, I have the following signature from the header:virtual bool DownloadNethraBootLoader(size_t DataSize, const BYTE *Data, PercentUpdate_CB CallBackFunction=NULL, void *Context=NULL);

I can manipulate a byte array using the Qt type QByteArray. I need to pass that to the second parameter of the function. Is there a proper conversion or cast that works. I've only been working with Qt 4.8.0 for a few weeks.

Thanks Leon for the quick response. I was hoping though for a direct conversion. This may be a bit convoluted. I may be better off dealing with a array of bytes using mem functions etc. I was trying to stay within the Qt class libraries.